The present invention relates to a lock-up torque converter and more particularly to a compact arrangement of a damper which provides a driving connection between a lock-up clutch piston and a turbine runner.
A vehicle installed with a torque converter will show a poor fuel economy because of the fact that any fluid coupling experiences some degree of slip. A various kinds of lock-up torque converters have been proposed in which a torque converter locks up by means of a built-in clutch in a predetermined (high speed) operating range of a vehicle when torque variation of an engine is not experienced as a problem.
In a known lock-up torque converter, a damper for providing a driving connection between a clutch piston and a turbine runner is located in a space available between an outer periphery of the clutch piston and an outer periphery of the turbine runner and it is drivably connected at an inlet element thereof to the clutch piston and at an outlet element thereof to the turbine runner.
A problem with this damper arrangement is that since the damper is spaced radially outwardly from the axis of rotation about which the clutch piston and the turbine runner rotate by a considerable amount, the damper is thrown outwardly with such a large centrifugal force as to induce malfunction of the damper when the vehicle operates at high speeds.
In another known lock-up torque converter, a damper is located between an inner periphery of a clutch piston and an inner periphery of a turbine runner.
A problem with this known arrangement is that since the damper is spaced radially outwardly from the rotation axis by a relatively small amount as compared to the damper arrangement mentioned before, a large damper has to be provided so as to afford to carry or transmit a large amount of torque and it requires complicated construction to drivably connect the damper to the turbine runner, as a result of which the entire axial length of this known arrangement becomes long.